ES2644845T3 - A gondola for a wind turbine generator that includes a lifting device - Google Patents

Description

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

60

65

DESCRIPTION

A gondola for a wind turbine generator that includes a lifting device Technical field

The invention relates to lifting devices used in wind turbine generators, particularly gondolas of wind turbine generators.

Background

Large-scale, horizontal-scale wind turbine (HAWT) turbine generators typically comprise a set of rotor blades mounted on a support structure that normally takes the form of a tubular tower. In said HAWT, the generation components that include the generator, the gearbox, the drive train and the brake assembly are located at the top of the tower in a gondola behind the hub of the rotor blades.

It is known to install lifting devices inside a gondola to help personnel install heavy components. For example, WO2012 / 107049A1 describes a boom crane that is mounted within a gondola of a HAWT, in which the boom is movable in elevation and in azimuth relative to the gondola. In a collected position, the boom crane rests inside the gondola and is covered by a roof. However, the boom crane can move to an unfolded condition in which the boom is able to reach beyond the ceiling level to access other parts of the gondola. For example, the boom is able to reach a helicopter platform to transfer loads from the platform to the inside of the gondola body, but it is also able to reach beyond the side of the gondola to lift loads from the surface if necessary.

The almost continuous operation of wind turbines generates vibrations. It is believed that these vibrations can lead to dynamic loads such as oscillations of the boom that can cause wear or that may adversely affect the long-term reliability of the lifting devices housed within the gondola. The invention has been conceived against this background.

Summary of the invention

Against this background, the invention provides a gondola for a wind turbine generator comprising a crane and is defined in the attached claim 1. In particular, the crane is articulated on a fixed base to the gondola, the crane including a cantilever telescopic boom, a main winch with a lifting line and respective azimuth and elevation drive units to move the boom in azimuth and in elevation in relation to the gondola. The crane has an unfolded condition in which the boom is mobile in azimuth and elevation and a pickup condition. According to the invention, the gondola comprises a support structure against which the boom is placed to rest in said pick-up condition. When in the pick-up condition, the boom is located within a predetermined position in which it is held to rest at a point along its length against the support structure. The expressions maintained or maintained to rest or resting against, as used herein, denote a condition such that said support structure prevents oscillations of said boom during operation of said turbine, that is, a situation in which The support structure prevents oscillations of the boom that could otherwise take place during the operation of the turbine. Preferably, the boom can make contact with the support structure or stay in close proximity against the support structure. Even preferably, the boom in its pick-up condition can exert minimal pressure against the support structure. According to the invention, the lifting line of the main winch is brought to a reference position in relation to the gondola or in relation to particular components of the gondola when the crane is in its collection position.

Beneficially, therefore, the invention provides a lifting apparatus in which the boom is supported against a boom rest and thereby prevents the movement of oscillation of the boom. As mentioned above, wind turbine generators generate significant dynamic loads during use that can strongly influence the cantilever arrangement of a boom with respect to its base, particularly if the frequencies of the oscillations coincide with the natural frequency of the boom crane. This can increase wear on the component parts of the crane on which the boom is mounted. Maintaining the boom of the crane against a fixed support reduces the dynamic loads on the crane when it is in the collected position thereby improving the reliability of the crane.

In principle, the boom can be held against a support at any point along its length so that it inhibits unwanted oscillations of the boom. However, in one configuration, the support structure is positioned so that a free end of the boom rests against it, which provides the most effective damping of dynamic loads through the crane.

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

60

65

According to preferred aspects of the invention, the main winch may be operative to lift useful loads both in a deployed condition and in a pickup of the boom. According to the invention, the lifting line of the main winch is advantageously placed in a reference position when the crane boom is in a collected position. The reference position can be advantageously arranged in a predetermined position in relation to a component or part of the gondola. In particular, a predetermined position of the lifting line can rest directly above a component or a part of the gondola. Advantageously, the reference position of a lifting line of the main winch can be arranged above an opening or hatch of the gondola on a floor thereof through which loads can be raised or lowered vertically between the interior and the exterior of the gondola.

In one configuration, the crane is configured to be able to lift useful loads when it is in the collected condition. Indeed, therefore, the crane can become a static crane when it is in the collected condition. A benefit of this is that the crane can be operated when it is in the condition collected by personnel who otherwise are not sufficiently qualified to operate the crane when it is in the deployed condition. Optionally, the azimuth and crane lift actuators can be disabled in a condition collected from it while the main winch can remain enabled for use in said collected condition. An additional benefit of the crane operation in its collected configuration arises because the crane is in a predetermined position with its elevation line in a reference position known for use. The operation of the main winch of the crane with its lifting line in a reference position eliminates the need for a trained or certified operator to position the crane for use and ensures that the use of the crane in the collected position is restricted to operations of elevation, that is to say elevation and descent of loads, in a given vertical location. Indeed, in embodiments, the gondola crane can be used in its collected position as a simple elevator in particular for lifting loads through a hatch on the floor of the gondola or for lifting loads in relation to a location or particular component inside the gondola.

According to the invention, the boom of the lifting apparatus is movable in azimuth, elevation and telescopic movement when it is in the deployed condition which provides the greatest flexibility of reach for the crane. In certain embodiments, the crane actuator relevant for azimuth and boom lift movement can be disabled when the crane is in a parked mode with the boom in its collected position. Optionally, the telescopic action of the boom can also be disabled in embodiments of the invention, in particular in a position collected from the boom.

Optionally, when in the collected position, the crane can be located so that its elevation line is in a reference position above or adjacent to an opening in a gondola floor located so that the crane is capable of lifting loads to a tower where the gondola is mounted, during use. Alternatively, when in the collected position, the crane can be located so that its elevation line is in a reference position above or adjacent to an opening in a floor of the gondola located so that the crane is capable of lifting loads outside a tower where the gondola is mounted, during use.

The support structure does not have to be part of the crane and, as such, can be external to the crane. For example, the support structure for the boom can be provided by an internal frame structure of the gondola. Alternatively, the support structure can be mounted directly to or between one or more walls of the gondola. Providing the support structure as part of the gondola's internal frame structure provides the most effective route to distribute the loads from the boom to the interior of the main tower structure.

In one embodiment, the boom can rest from below against a support surface of the support structure but, in an alternative embodiment, the boom can rest against a support surface of the support structure from above.

The boom crane can be configured with a resting element to engage against or with the support structure. The resting element can be an integral part of the crane or can be fixed extrafibly to it, which allows the resting element to be updated in any suitable crane.

In a further optional embodiment, a pressure indicating device configured to generate a signal indicative of the pressure applied to the support structure by the boom can be provided. The pressure indicating device can be configured in particular to generate an alarm signal if the pressure applied to the support structure by the boom exceeds a predetermined threshold. Consequently, an operator can optionally determine and indicate how much load is applied to the support structure. In addition, an operator can be indicated by means of an alarm or warning signal, if a load limit is reached or exceeded on the support structure. A load limit can be predetermined and entered into a gondola or crane control system. The provision of a pressure indicating device can thereby prevent overload of the support structure and / or inappropriate loading of the gondola. In certain embodiments, a pressure sensor of the pressure indicating device may be provided in a particular support structure on a support surface thereof. Alternatively, a pressure sensor of the pressure indicating device may be provided in the resting element.

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

60

65

In one embodiment, the crane is mounted in a housing for a rotating component of the gondola, such as a low speed shaft that includes bearings of the main shaft, gearbox and the like. This housing is large and stable and provides a secure mounting point for the crane.

Some additional optional features of the invention are defined in the attached subclaims 2-13. The invention also encompasses a method for the operation of a gondola crane as defined in claim 14. An additional optional feature thereof is defined in the attached subclause 15.

Consequently, the invention also encompasses a method for the operation of a crane in a gondola, the method comprising the transition of a crane from a deployed mode of operation to a collected mode of operation by carrying the crane boom to rest against a structure. for supporting the gondola and additionally by disabling the respective lifting and azimuth motion actuators of said crane. The method further comprises the operation of the crane in its collected mode as a static elevator by using a main winch of the crane while the boom is in its collected position. Preferably, the method includes raising or lowering loads through an opening in a floor of the gondola while the boom is in its collected position and with the crane in its collected mode of operation. Optionally, advantageously, the method includes the measurement of the load applied to the support structure, in particular to a support surface thereof and the generation of a signal if a predetermined load is exceeded. The method may additionally include the entry into a control system of said crane or gondola of a threshold load level at or above which an alarm signal is generated. The method may additionally include measuring the load between respective contact surfaces of said crane boom and said support structure. The method may additionally include measuring the load between respective contact surfaces of said crane boom and said support structure by measuring the load on a contact surface of said crane boom. Alternatively, the method may additionally include measuring the load between respective contact surfaces of said crane and said support structure by measuring the load on a contact surface of said support structure which may in particular be a support surface. Of the same.

Additional optional steps of the method are described in accordance with aspects of the invention throughout the present specification. It will be appreciated that the preferred and / or optional features of the invention can be combined together or individually with the invention defined according to claim 1 or 14.

Brief description of the drawings

To provide a more complete understanding of the invention, reference will now be made, by way of example, to the following drawings in which:

Figure 1 is a schematic view of a horizontal axis wind turbine generator;

Figure 2 is a perspective view of a gondola of a wind turbine generator incorporating a lifting apparatus;

Figure 3 is a perspective view of part of the gondola of Figure 2, but from a different angle of vision, and showing the lifting apparatus in a "collected" condition;

Figure 4 is a more detailed view of a structural framework of the gondola of Figure 3 showing a support structure for the lifting apparatus; Figure 5 is an enlarged view of an area of Figure 4;

Figures 6 and 7 are perspective views, from alternative viewing angles, illustrating how the lifting apparatus is mounted on the gondola;

Figure 8 is a schematic view of the gondola illustrating the lifting apparatus operating in the collected mode and

Figure 9 is a schematic view similar to Figure 8 but showing an alternative configuration of the gondola and its associated crane.

Detailed description

With reference to Figure 1, a horizontal axis type (HAWT) wind turbine 2 comprises a gondola 4 mounted on the top of a tower 5 which is mounted in turn on a foundation or pedestal 6. The gondola 4 includes a hub 8 at its front end which carries with it a set of rotor blades 10. Three rotor blades 10 are shown in this embodiment, as is common in large-scale shared generators, although those skilled in the art will appreciate that others are acceptable. shovel numbers.

At this point it should be noted that Figure 1 has informational purposes only, so that it is not to scale and is not intended to be a realistic representation of a wind turbine generator. It should also be noted that other tower constructions are known, for example towers defined by a structural grid framework.

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

60

65

To allow energy to recover from the wind-driven rotating blades 10, the gondola 4 houses a generator set 12, represented here in broken lines, which is driven by the hub 8 through a low-speed drive shaft. 14. The generator set 12 is typical of a HAWT and includes a gearbox 20 that elevates the rotation speed of the low speed drive shaft 14 to a high speed output shaft 22 which is used to drive an electric generator 24. The generator 24 produces the output of an alternating current (AC) at a voltage and frequency that is largely determined by the rotation speed of the hub 8 when driven by the rotor blades 10.

To allow variable speed operation of the wind turbine generator 2, the alternating current produced by the generator 24 is first converted, or "rectified", to direct current (DC) and then converted back to an alternating current (or " inverted ”) at the correct frequency and voltage to integrate with the frequency and voltage required from the national power grid system through the power line 26. The rectification and inversion process is handled by a power system 28 that this contained in an internal structure of the tower 30 to which the generator 24 is electrically connected by means of a high voltage AC current line 32.

The need for routine maintenance of the generator set 12 or the need for repair or replacement of components of the generator set 12 requires that personnel have access to the interior of the gondola 4. This can be achieved by providing a suitable stair system within the tower so that staff can climb to the top of the tower. The alternative access options for personnel is to take it in flight to the wind turbine generator by means of a helicopter and off-hook on the gondola, or the personnel is transported to the gondola by a “capsule lift platform” provided by a ground-based crane . However, although personnel can gain access to the gondola in this way, this is much more difficult for heavy pieces of equipment, for example drive shafts or gearbox components, to be transported to the gondola in the same way. .

It is against this context that the invention will now be described with reference to Figures 2 to 8 showing a gondola 4 having an integrated lifting apparatus 40 that addresses the problems explained above.

The lifting apparatus 40 includes a crane 42 that is mounted on the gondola 4. In this embodiment, the crane 42 is a telescopic boom crane comprising a crane base 44 fixed to the gondola and a mobile boom 46 that is articulated on and cantilever from the base 44. A motorized main winch 45 is provided in a base area of the crane 42 in particular at a base end of the boom 46 that unwinds a main lift line 43, for example in the form of a cable steel that is directed through a suspension point at a free end 47 of boom 46 to end in a lifting bracket, such as a hook 49. The crane 42 also includes a feeding system, shown here generally by the number reference "51", which is configured to operate the telescopic, lifting and turning operations (ie azimuth) of the boom 46 relative to the base 44. The feeding system may in particular be an electroh feeding system hydraulic. Said boom crane is familiar to the person skilled in the art. Although the crane 42 could be mounted on the gondola 4 in several ways, in this case the base 44 of the crane 42 is mounted in a housing of the tree 9 of the gondola 4, as shown in Figures 6, 7 and 8. Note that the shaft housing 9 provides a bearing support for the drive train components such as the generator and particularly the low speed shaft.

The crane 42 is configured to be placed in two conditions, or modes: i) a first "collected" condition in which the boom 46 is housed within the gondola 4 and ii) a second "unfolded" condition in which the boom 46 It is mobile with respect to the base 44 of the crane 42.

As shown perhaps more clearly in Figure 3, with the base 44 of the crane 42 mounted on the bushing of the bushing 9, the boom 46 can generally extend along the central line of the gondola 4 when placed in the collected condition.

However, when placed in the unfolded condition, the boom 46 is operative to extend out of the confines of the gondola 4 so that it reaches above a set of doors that can be closed 48 defining a roof of the gondola 4 when They close. Figures 2 and 8 illustrate this particularly clearly in which the boom 46 extends beyond an upper platform 50 of the gondola 42. In this way, therefore, the boom 46 can oscillate beyond the side of the gondola so that it is capable of lifting useful loads from the ground level to gondola 4. The boom 46 can also be extended telescopically so that it is able to reach a maintenance platform shown in this case as mounted on the rear from the top platform of the gondola 4, and is also able to reach the hub 8 and through a rear maintenance hatch (not shown) of the gondola 4.

Having described the overall operation of the crane 42 in general terms, the explanation will now go to the more detailed construction of the gondola 4.

The gondola 4 comprises an internal frame structure 54 that supports an outer liner 56. The outer liner 56 defines the upper platform 50 and side walls 58 of the gondola 4 and can be formed to

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

60

65

from any suitable material as is known in the art. ^ However, however, the outer coating 56 will be in the form of metal panels, for example of steel or aluminum, or, alternatively, of a composite construction, for example GRP (plastic reinforced with fiberglass).

The internal frame structure 54 includes a main frame 60 and an outer sub-frame 62. The main frame 60 provides the gondola 4 with structural strength while the sub-frame 62 supports the outer liner 56.

The main frame 60 comprises a triangulated network of frame elements 64 (of which only some are labeled) that is connected to an orientation platform 66 of the tower 5, as schematically illustrated in Figure 8. Said configuration is generally known in the art.

The functional components of the gondola 4 are mounted on the main frame, for example, the main bushing bearing 9, the gearbox, the generation equipment and the like, although it should be appreciated that many of these components are not shown in the figures for clarity However, the main bushing bearing 9 is shown in Figure 3, positioned on the left side of the gondola 4.

The subframe 62 comprises a plurality of vertical elements 65 or "braces" that are generally C-shaped and are connected between upper and lower horizontal rails 64a, 64b of the main frame 60 to provide a frame-like structure for the support of the outer covering 56.

As can be seen in Figure 3, the crane 42 is fixedly mounted on the main hub bearing 9 so that the boom 46 extends in the longitudinal direction "L" of the gondola 4 and is surrounded by the main frame 60 , when crane 42 is in the collected or "parked" condition. In this condition, the crane 42 is configured so that the boom 46 remains supported against a support structure 70. More specifically, and with particular reference to Figures 4 and 5, the support structure 70 in this embodiment is an element of "I-beam" or "mensula" type support that extends between the first and second frame elements 63 that flank the mensula and extend obliquely therein. In the embodiment illustrated in Figure 3, the support structure 70 has a support surface 72 on an upper face thereof although in certain embodiments of the invention, the support surface may be on a lower face thereof. The arrangement of the boom 46 resting against the support structure 70 is primarily aimed at preventing oscillations of the boom 46 during the operation of the turbine whose oscillations may arise as a result of vibrations of the turbine's operational elements during operation. Therefore, in a position collected from boom 46 as illustrated, the loads generated by the boom weight itself are supported by crane 42. Moreover, a pressure gauge can be provided which has in particular a pressure sensor that can be arranged between boom 46 and support structure 70. The pressure gauge may be configured to produce a signal indicative of the amount of load applied to support structure 70 by boom 46. In certain embodiments, the pressure gauge It can be configured to emit a signal that can be an alarm signal at a predetermined load threshold defined in the pressure gauge. This may serve to prevent excessive force from being applied to the support structure 70 when the boom 46 is brought to rest against it or at any time while the boom 46 is resting against the support structure 46. It can thus be prevented that inappropriate loading is applied to the support structure 70 by the boom 46. This aspect also prevents undue pressures from being applied to the gondola 4 by the action or use of the lifting device 40 or crane 42. A pressure sensor can be placed for example on a support surface 72 or on a contact surface of the boom 46.

Although it is feasible that a support structure 70 could be provided to support the boom 46 at any point along its length, in this embodiment the free end 47 of the boom 46 has a contact surface that rests against the support member 72 More specifically, the free end 47 of the boom 46 includes a rest in the form of an extension element 74 made as an L-shaped flange that is screwed on or otherwise fixedly fixed to the free end 47 of the boom 46. The flange 74 rests the boom 46 against the support element 72. The support element 72 therefore makes slight contact with the boom 46 and this keeps the boom 46 in position and against oscillations when it is in the collected position. During the operation of the wind turbine, the crane 42 is subjected to a significant dynamic load that can be transmitted to the crane 42 through its fixed base 44 to the gondola 4 and this can have a detrimental effect on the long-term reliability of The crane 42. Therefore, a benefit of the support structure 70 is that it provides support to the boom 46 when it is in the collected condition, thereby reducing the load on the crane 42 during the operation of the wind turbine. The reliability of the crane 42 is improved and wear can be reduced.

In a further feature of the lifting apparatus 40, the crane 42 is configured so that the feed system 51 of the crane 42 is disabled when placed in the collected condition. The crane functions that enable boom 46 to be raised and turned in azimuth, are therefore not available to an operator in the collected condition. Optionally, the crane can be configured so that the telescopic extension and retraction function of the crane 42 is also disabled when the boom 46 is in the collected condition. However, in the collected condition, the crane 42 can preferably be configured so that the main winch 45 is still operative to such a degree that it is capable of lifting useful loads with the boom 46 in a

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

55

60

65

static position. In effect, therefore, the boom crane 2 becomes a static lift.

In this illustrated embodiment, the collected condition of the free end 47 of the boom 46 is shown located in a predetermined position with the lift line 43 suspended vertically in a reference position above the orientation platform 66 of the gondola 4. The platform Orientation can define an opening and can comprise a hatch (not shown). The crane 42 is therefore operative in this collected configuration so that the lift line 43 is able to pass through the orientation platform 66 into the tower which allows useful loads to be lowered from the gondola 4 to inside the tower or rise inside the gondola 4 from inside the tower 5. In fact, therefore, in the collected condition the crane 42 becomes a simple elevator without the ease of the boom 46 being turned , elevated or telescopically operated. This allows the crane 42 to be operated by personnel without adequate qualification which gives greater flexibility for the maintenance of the wind turbine. When used as a static lift, as described, the loads placed on the boom 46 by the carrier of useful loads on the lift line 43 are carried by the crane 42 through its base 44 or at least mostly by the crane 42. In certain embodiments, a pressure gauge may emit a signal if the load applied by boom 46 on the support structure 70 exceeds a predetermined limit.

Figure 7 illustrates an additional component of the lifting apparatus 40 that is not shown in the corresponding view of the lifting apparatus 40 in Figure 6. As shown in this case, the base of the crane 44 is provided with first and second platforms 80 mounted horizontally that are mounted on both sides of base 44. Platforms 80 allow maintenance personnel to access crane components for inspection and maintenance purposes.

Some variations of the specific embodiment of the invention described with reference to Figures 2 to 8 have already been mentioned above. Others will be explained now.

In the embodiments described above the crane is configured so that in a deployed condition the boom 46 is operative to extend in elevation, orientation and extension or retraction. The free end 47 of the boom 46 can extend in particular from the confines of the gondola 4 while, in a collected condition, the free end 47 of the boom is positioned in a predetermined position with its free end and main lift line in a position of reference, for example, on the orientation platform 66 of the gondola 4. The elevation line 43 can thus be extensible downwards inside the tower 5. However, in a further configuration, the reference position of the Elevation line 43 may be above an opening that allows elevation line 43 to extend downwardly outside the tower, and this is illustrated in Figure 9. In this figure, the same reference numbers are used for refer to components in common with previous embodiments. As can be seen in this embodiment, the gondola 4 extends backwards from the tower 5 to define a significant hanging part. The floor 90 of the hanging part defines a hatch-shaped opening 92. The hatch 92 may be permanently open or may have a means to close it, such as a pivot door 94 as shown in this case.

The crane is configured so that the free end 47 of the boom 46 is positioned on the hatch 92 when the boom 46 is in the collected or parked position resting against a support surface 72 of the support structure 70. The hook 49 in the The end of the elevation line 43 is therefore capable of extending downwards through the hatch 92 to descend articles to the ground or lift articles to the gondola 4 from the ground.

The embodiment of Figures 2 to 8 could also be configured in a similar manner so that a suitable hatch is provided at a location that can be reached by the crane, for example on a rear wall of the gondola, so that they can be raised and descend items outside tower 5.

It should be noted that in all the embodiments it has been described that the flange 74 is fixedly removable to the free end 47 of the boom 46, for example by screws, and it should be noted that this is not essential and that instead the flange 74 could be formed as an integral part of the gable. For example, the flange 74 could be welded to the free end 47 of the boom 46, or the boom 46 could be shaped specifically to define the flange 74. However, fixing the flange 47 to the boom 46 in an extrafble way allows a crane to be selected "Commercially available" and equipped with said flange 74. This allows different cranes to be selected and equipped as necessary. In certain embodiments, a pressure sensor of a pressure gauge may be included in a contact surface of the flange 74.

In the above explanation, the boom 46 of the crane 42 rests against a support structure 70 which is realized by a part of the internal frame structure 54 of the gondola 4. However, it should be appreciated that other configurations are possible to support the boom 46 of the crane 42. For example, a support bracket suitable for extending directly between opposite side walls 58 of the gondola 4, or for extending upward from the floor of the gondola (not shown) could be arranged. An additional alternative is for a suitable structure to be integrated into the base 44 of the crane 42 that directly reaches to support the boom 46 at some point along its length, preferably at its free end. Also, although in the realizations

described above the boom is supported from the bottom, it is also possible that the support structure is configured to provide support to the boom from the top.

Additionally, although it has been described that the free end 47 of the boom 46 is supported, it should be appreciated that in principle any part of the boom 46 can be supported. Since the boom crane is essentially a cantilevered structure, the support of the cantilever free end of the boom provides the most effective reduction in stresses on the base 44 of the crane 42. However, the supports at other points along the length of the boom 46 may also provide an advantage.

10 Crane 42 has been described as a telescopic boom crane. This crane is useful because it has three degrees of freedom (rotation, elevation and telescopic) and is thus open to access many areas of the gondola.

Although the lifting apparatus has been described in the context of being installed in a gondola of a wind turbine generator, it can also be installed in other locations, for example within a tower structure of the wind turbine generator.

Claims (15)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 1. A gondola for a wind turbine generator comprising an articulated crane on a fixed base to said gondola, said crane including a cantilever telescopic boom, a main winch with a lifting line and respective azimuth and elevation drive units for moving said boom in azimuth and in elevation relative to said gondola, said crane having an unfolded condition in which said boom is movable in azimuth and elevation and a collected condition, in which said gondola comprises a support structure against which said boom is placed to rest in said collected condition thereof and in which when it is in said collected condition said boom is located within a predetermined position in which it is maintained to rest at a point along its length against said structure of support and in which said lifting line is in a reference position in relation to said gondola when said crane is in its collected condition. 2. The gondola of claim 1, wherein when it is in said reference position, said elevation line is located above an opening in said gondola. 3. The gondola of claim 2, wherein said lifting line of said main winch is operative to lift useful loads both in said deployed condition of said boom, and also in said collected condition so that said crane is capable of lifting Useful loads outside a tower on which said gondola is mounted. 4. The gondola of claim 2, wherein said lifting line of said main winch is operative to lift useful loads both in said deployed condition of said boom and also in said collected condition so that said crane is capable of lifting loads useful through a tower on which said gondola is mounted. 5. The gondola of claim 1, wherein said boom includes a resting element that is maintained by said support structure when said crane is in said collected condition. 6. The gondola of claim 5, wherein said resting element is removable from said boom. 7. The gondola of claim 1, wherein a pressure indicating device is configured to generate a signal indicative of the pressure applied to said support structure by said boom. 8. The gondola of claim 7, wherein said pressure indicating device is configured to generate an alarm signal if said pressure applied to said support structure by said boom exceeds a predetermined threshold. 9. The gondola of claim 1, wherein a free end of said boom rests against said support structure in a position collected from said crane. 10. The gondola of claim 1, wherein the crane includes a maintenance platform on which personnel can remain to access the crane components. 11. The gondola of any claim 1, wherein said support structure is integral with an internal gondola framework. 12. The gondola of claim 1, wherein said support structure is mounted directly on or between one or more walls of said gondola. 13. The gondola of any preceding claim, wherein said crane is mounted in a housing for a rotating component of said gondola. 14. Method for the operation of a crane in a gondola according to any previous claim, said method comprising placing said crane from a deployed condition to a condition collected by bringing said boom of said crane to rest against said support structure and disabling the respective lifting and azimuth motion actuator of said crane, said method further comprising the operation of said crane as a static elevator using said main winch in said collected condition. 15. Method according to claim 14, which further includes determining the load applied to said support structure by said boom and the generation of a signal when said load exceeds a predetermined threshold.